Fléchette

The Fléchette is an artifact from Hexen. It is a small flask of green liquid, and its effects differ between classes:
 * In the hands of the Cleric, it is dropped directly onto the ground beneath the player and will quickly explode into a poisonous green gas cloud, choking any monster or player that walks through it. The Cleric's fléchette attack, with its lingering cloud, is considered by most players to be the most effective of the three, especially because he can lure monsters into the gas cloud where they take damage and are easy targets for cheap shots.
 * The Mage's fléchettes act in almost exactly the same way as Heretic's Timebomb of the Ancients. They are dropped on the spot where the player stands, and explode for heavy damage after one second.
 * When used by the Fighter, it is thrown like a grenade, and will bounce on the ground and explode after three seconds or on contact with a monster.

The fléchette is one of the most common artifacts in the game, and a player may carry 25 at one time.

Strategies

 * The cleric's poison clouds and the mage's time bomb will cause damage even against monsters that have shields up, such as centaurs, slaughtaurs and the Heresiarch. The cleric's gas has a particularly powerful effect on centaurs and slaughtaurs as they will be stunlocked upon entering the cloud and will remain taking damage in it until it wears off or they die.
 * The cleric can also combine the fléchette with a Disc of Repulsion to make a projectile attack. Once the gas cloud appears, it can be launched at an enemy with the disc. The cloud's impact deals a massive amount of damage, instantly destroying any non-boss enemy upon contact. Monsters with the boss flag are exempted from damage.
 * The fighter can kill chaos serpents with two or three direct hits from fléchettes. Given the rapid rate at which they can be thrown, this is one of the fastest ways a fighter can kill this enemy short of using Quietus or other artifacts, and is especially helpful early in the game.
 * The mage can use his wand (or other weapon) to injure a centaur or slaughtaur so that he goes into his defensive stance, then leave a "surprise" in front of him. With proper spacing and timing, the fléchette will explode just as the centaur walks onto it, possibly killing it with as little as one wand shot plus a fléchette.

Appearance statistics
In the IWADs the fléchette is first encountered on these maps per skill level:

The IWADs contain the following numbers of fléchettes per skill level:

Other games
Heretic and Hexen II have similar items, the Timebomb of the Ancients and the Glyph of the Ancients respectively, with the effects of the latter also slightly different depending on the player's character class.

Trivia

 * When a fléchette is used, the game checks for the player's class, whether it's a Cleric, or if not a Cleric then whether it's a Mage, and if the class is neither Cleric nor Mage then it defaults to Fighter. If a player has been morphed by the Porkalator, because his class is no longer Cleric or Mage, but pig, a morphed Cleric or Mage will throw fléchette grenades like the Fighter does.
 * Gas clouds can still be generated by the Fighter or the Mage, but only by shooting mushrooms that may be found in certain areas, such as the Orchard of Lamentations in Episode 3.
 * Fléchette means "dart" in French. In English, it refers to first used in WWI.